A variety of flavorants have been developed and proposed for incorporation into tobacco products. Illustrative of such tobacco flavorants are those described in U.S. Pat. Nos. 3,580,259; 3,625,224; 3,722,516; 3,750,674; 3,879,425; 3,881,025; 3,884,247; 3,890,981; 3,903,900; 3,914,451; 3,915,175; 3,920,027; 3,924,644; 3,937,228; 3,943,943; 3,586,387; 4,379,754; and the like.
The use of carboxylic acid flavorants for tobacco products has received acceptance because of the desirable aroma and flavor characteristics which they impart to the smoke (J. C. Leffingwell, H. J. Young, and E. Bernasek, "Tobacco Flavoring for Smoking Products," R. J. Reynolds Tobacco Company, Winston-Salem, 1972). Specifically, acetic acid is commonly used as an ingredient of a Latakia tobacco flavoring formulation (J. Merory, "Food Flavorings," AVI Publishing Company, Incorporated, Westport, Conn., page 420, 1968). Isovaleric acid and 3-methylvaleric acid are major ingredients in a Turkish tobacco flavor formulation described in U.S. Pat. No. 3,180,340. Desirable flavors have been imparted to cigarette smoke by the addition of 4-ketoacids to tobacco in the manner described in U.S. Pat. No. 3,313,307.
Numerous methods of adding flavorants to tobacco smoke are known. Typically the known methods suffer from one or more disadvantages, particularly when the flavorant is a low molecular weight carboxylic acid. Specifically, some of these acids are highly volatile and possess objectionably strong odors that render them difficult to use in bulk amounts required for manufacturing purposes. In addition, some of the volatile acids may impart an undesirable pack aroma.
In an attempt to alleviate some of these problems, carboxylic acids have been incorporated in tobacco as part of a compound (i.e., an organic acid release agent) in such form that upon burning of the tobacco the compound will liberate one or more organic acids imparting a selected and desired flavor and aroma to the smoke. While considerably more satisfactory than earlier attempts, even this technique has evidenced certain drawbacks.
U.S. Pat. No. 2,766,145 through U.S. Pat. No. 2,766,150 describe a variety of methods for treating tobacco with compounds that release carboxylic acids on pyrolysis. The U.S. Pat. No. 2,766,145 patent describes esters of monohydric and polyhydric compounds. The hydroxy compounds may be aliphatic or aromatic in nature.
The U.S. Pat. No. 2,766,146 patent describes esters of a sugar acid selected from aldonic acids and uronic acids. U.S. Pat. No. 2,766,150 describes nonvolatile synthetic polymers or condensation products, preferably those related to polyvinyl alcohol and vinyl alcohol-type condensation products. On pyrolysis, the carboxylic acid is liberated to flavor the smoke. These polymers have a distinct disadvantage in that they generally have high molecular weights and are more difficult to solubilize for application on tobacco.
Other patent references which disclose tobacco flavorant compositions that release carboxylic acids on pyrolysis include U.S. Pat. No. 4,036,237 and U.S. Pat. No. 4,171,702.
There is continuing research effort to develop improved low delivery smoking compositions which generate mainstream smoke with flavorant-enhanced taste and character under smoking conditions.
Accordingly, it is an object of this invention to provide smoking compositions having incorporated therein a flavorant component which is characterized by lack of mobility and/or volatility at ambient temperature.
It is another object of this invention to provide smoking tobacco compositions having incorporated therein a flavorant-release composition which under normal smoking conditions imparts improved flavor to mainstream smoke and improved aroma to sidestream smoke.
It is a further object of this invention to provide novel dioxane diester compositions which are adapted to be incorporated into tobacco compositions, and which under normal smoking conditions release a carboxylic acid type of volatile flavorant into cigarette smoke.
Other objects and advantages of the present invention shall become apparent from the following description and examples.
This patent application is related in subject matter to copending patent application Ser. No. 603,035, filed Apr. 23, 1984.